Bird flocks can out-perform any number of Blue Angels, and humans have long been in awe of the mystery of how they can fly so close together at such high speeds without constantly colliding with each other. A team from the University of Cambridge has just published a study in Animal Behavior that sheds new light on how the awesome avians can move so well. The UK researchers studied common British flocking birds, jackdaws and rooks, both related to the American crow, but the results might offer clues to the collective behavior of birds of any species.
We’ve all seen it — dozens, hundreds, or even thousands of speed-racer bird flocks flying in one direction, only to turn on a dime when they spot a hawk. Compare that to the Daytona 500, where we may have humans racing less than 50 cars, and there are still regular crack-ups.
Early 20th century researchers, unable to explain how the birds could communicate that effectively that fast, even suggested that ESP, mental telepathy, or a so-called biological radio to account for flock behavior. “The fact that we weren’t hooted out of town is an indication of how desperate we were to explain this stuff,” an older researcher told Audubon writer Peter Friederici a few years ago.
Now the UK team has teased out a few clues that may explain more about how bird flocks work. The birds tend to sort themselves out so that they’re flying with members of their own species, and paired birds try to fly closest to their mates. Presumably, they are flying closest to the very individuals whose body language they can read the most intimately. With rooks in particular, they also confirmed that the largest and most dominant birds will take the lead. Assuming that the strongest birds at the top of their game can make the most effective leaders, it starts to make sense how fast-flying birds can cooperate without knocking heads all over the place.
Richard Gibbons, a well-known Louisiana bird expert, captured this 2009 You Tube video of the tree swallow “tornado” made up of four million birds that visit the sugar cane fields in the Vacherie, Louisiana area each winter.
I witnessed this event myself in the same spot in 2010, and watching millions of birds form a funnel cloud to drop into the fields will knock you off your perch. Now that’s a bird flock.
[sandhill cranes photo courtesy Roger Williams and Elaine Radford]